Simple performance test for string concatenation operations

StringCOncatTest.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;

namespace StringConcat
{
    class Program
    {
        private static int noLoops = 100000;
        
        static void Main(string[] args)
        {
            Console.WriteLine("Adding one strings");
            RunIterations("Simple concatenation by using + operator", foo => foo = "a");
            RunIterations("string.Format", foo => foo = string.Format("{0}", "a"));
            RunIterations("StringBuilder", foo =>
                                               {
                                                   var builder = new StringBuilder(foo);
                                                   builder.Append("a");
                                                   foo = builder.ToString();
                                               });
            Console.WriteLine();

            Console.WriteLine("Adding two strings");
            RunIterations("Simple concatenation by using + operator", foo => foo = "a" + "lorem");
            RunIterations("string.Format", foo => foo = string.Format("{0}{1}", "a", "lorem"));
            RunIterations("StringBuilder", foo =>
            {
                var builder = new StringBuilder(foo);
                builder.Append("a");
                builder.Append("lorem");
                foo = builder.ToString();
            });
            Console.WriteLine();

            Console.WriteLine("Adding six strings");
            RunIterations("Simple concatenation by using + operator", foo => foo = "a" + "lorem" + "ipsum" + "dolor" + "sit" + "amet");
            RunIterations("string.Format", foo => foo = string.Format("{0}{1}{2}{3}{4}{5}", "a", "lorem", "ipsum", "dolor", "sit", "amet"));
            RunIterations("StringBuilder", foo =>
            {
                var builder = new StringBuilder(foo);
                builder.Append("a");
                builder.Append("lorem");
                builder.Append("ipsum");
                builder.Append("solor");
                builder.Append("sit");
                builder.Append("amet");
                foo = builder.ToString();
            });
            Console.WriteLine();

            var a = "lorem";
            var b = "ipsum";
            var c = "dolor";
            var d = "sit";
            var e = "amet";
            var f = "consectetur";
            var g = "adipiscing";
            var h = "elit";
            var i = "Cras ";
            var j = "semper ";
            var k = "pretium ";
            var l = "nulla";
            var m = "quis ";
            var n = "tempus ";
            var o = "eros ";
            var p = "rutrum";
            var q = "rutrum";
            var r = "rutrum";
            var s = "rutrum";
            var t = "rutrum";
            var u = "rutrum";
            var v = "rutrum";
            var w = "rutrum";
            var x = "rutrum";
            var y = "rutrum";
            var z = "rutrum";

            Console.WriteLine("Adding a lot of strings");
            RunIterations("Simple concatenation by using + operator", foo =>
                                                                          {
                                                                              foo = a + b + c + d + e + f + g + h + i + j + k + l + m + n + o + p + q + r + s + t + u + v + w + x + y + z + a + b + c;
                                                                          });
//            RunIterations("string.Format", foo => foo = string.Format("{0}{1}{2}{3}{4}{5}{6}{7}{8}{9}{10}{11}{12}{13}{14}{15}{16}{17}{18}{19}{20}{21}{22}{23}{24}{25}", a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z));
            RunIterations("StringBuilder", foo =>
            {
                var builder = new StringBuilder(foo);
                builder.Append(a);
                builder.Append(b);
                builder.Append(c);
                builder.Append(d);
                builder.Append(e);
                builder.Append(f);
                builder.Append(g);
                builder.Append(h);
                builder.Append(i);
                builder.Append(j);
                builder.Append(k);
                builder.Append(l);
                builder.Append(m);
                builder.Append(n);
                builder.Append(o);
                builder.Append(p);
                builder.Append(q);
                builder.Append(r);
                builder.Append(s);
                builder.Append(t);
                builder.Append(u);
                builder.Append(v);
                builder.Append(w);
                builder.Append(x);
                builder.Append(y);
                builder.Append(z);
                builder.Append(a);
                builder.Append(b);
                builder.Append(c);

                foo = builder.ToString();
            });
            Console.WriteLine();



            var num = 10;
            Console.WriteLine("With a loop");
            RunIterations("Simple concatenation by using + operator", foo =>
            {
                for (var idx = 0; idx < num; idx++)
                {
                    foo += a;
                }
            });
            RunIterations("StringBuilder", foo =>
            {
                var builder = new StringBuilder(foo);
                for (var idx = 0; idx < num; idx++)
                {
                    builder.Append(a);
                }
                foo = builder.ToString();
            });
            Console.WriteLine();
        }

        private static void RunIterations(string label, Action<string> concatAction)
        {
            Console.WriteLine(label);
            Console.Write("01: ");
            Test(concatAction);

            Console.Write("02: ");
            Test(concatAction);

            Console.Write("03: ");
            Test(concatAction);

            Console.Write("04: ");
            Test(concatAction);

            Console.Write("05: ");
            Test(concatAction);

            Console.Write("06: ");
            Test(concatAction);

            Console.Write("07: ");
            Test(concatAction);

            Console.Write("08: ");
            Test(concatAction);

            Console.Write("09: ");
            Test(concatAction);

            Console.Write("10: ");
            Test(concatAction);

        }

        private static void Test(Action<string> concatAction)
        {
            var timer = Stopwatch.StartNew();
            for (var i = 0; i < noLoops; i++)
            {
                concatAction.Invoke(string.Empty);
            }
            timer.Stop();
            Console.WriteLine("Elapsed: {0}", timer.Elapsed);
        }
    }
}